A Virginia federal judge ruled this week that the law's key requirement for individuals to carry health insurance is unconstitutional. But even if the Supreme Court ultimately agrees, Obama has a readily available Plan B.
The administration could borrow a strategy that Medicare has used successfully for decades.
Medicare's coverage for doctor visits is totally voluntary and carries a separate premium, yet more than nine in 10 seniors sign up. The reason is simple: those who opt out when they first become eligible face a lifelong penalty that escalates the longer they wait.
The same kind of penalty could be incorporated into the health care overhaul in place of the current mandate that all Americans who can afford a policy must carry one. That would be a stiff nudge to get healthy people into the insurance pool, keeping premiums in check after the law takes away the ability of insurers to deny coverage to those in poor health.
Even if it doesn't work as well as for Medicare, it could still provide a strong incentive.
"It wouldn't be a nirvana solution," said health policy consultant Chris Jennings, but "it's better than nothing." A Democrat, Jennings served as a senior health care adviser to Bill Clinton and Hillary Rodham Clinton in the 1990s when the president and first lady unsuccessfully pushed for coverage for all.
Jennings believes the law as written would cover more people for a lower cost, but says "it would be irresponsible not to try an alternative" if the courts reject it.
Other prominent experts say Medicare's way could be more effective.
That's because the fines that back up the health care law are relatively low. When the individual coverage requirement takes effect in 2014 many people might still come out ahead by ignoring it. The fines they'd face could be lower than the premiums they would have to pay.
It's a "mandate lite," said economist Gail Wilensky, who ran Medicare for President George H.W. Bush. "A modification of what is done with seniors on Medicare would be a much more powerful tool. You don't have to buy insurance. But if you don't, the first time you come in, we're going to add a penalty that you'll have to pay for the next four or five years."
The White House says the law will ultimately be vindicated and there's no need for a fallback plan.
Nonetheless, the ruling by U.S. District Judge Henry E. Hudson, a Republican appointee in Richmond, Va., was the first successful challenge to the new law. Hudson ruled that Congress exceeded its constitutional authority to regulate interstate commerce by requiring individuals to obtain health insurance, whether through an employer, a government program or by purchasing their own policy.
Hudson denied the Virginia attorney general's request to strike down the law in its entirety or block it from being implemented while the Obama administration appeals. It could take a couple of years for the case to reach the Supreme Court and be decided.
Democrats were late to come around to the idea of an individual health insurance requirement. Most liberals still favor a government-run plan modeled on Medicare.
Requiring individual responsibility was the GOP alternative during the 1990s health care debate. Most Republicans have now abandoned it as big government intrusion, but Wilensky says she has no problems with the concept.
"As a society, we have made a commitment not to let people die in the street because of lack of medical care," she said, noting that hospital emergency rooms have to accept the uninsured. "It's not unreasonable to say that people be required to carry some sort of coverage."
The individual requirement got a boost when Massachusetts enacted it in 2006, after a bipartisan compromise between Republican Gov. Mitt Romney and Democratic state legislators. The idea rests on basic economics: insurance works best when everybody contributes to the pool. You can't get fire insurance after your house has burned down.
As a presidential candidate, Obama opposed the individual requirement as too costly for the average household. He embraced it after it became the only approach that could pass both the House and Senate. The legislation also provides tax credits to make premiums more affordable for millions.
If Obama has to switch to Medicare's approach, there's one caveat: It may not work as well with younger people.
"Sixty-five-year-olds are more risk averse than younger people," said Jennings. "If you are 65, you are not going to take the risk of being uninsured for a year. Someone who is 24, 28, or 32, would be more likely to take that risk."